Automatic ice makers that continuously produce large quantities of ice blocks are suitably used in kitchens of facilities such as coffee shops and restaurants, and other kitchens. These automatic ice makers include an injection type automatic ice maker that continuously produces ice blocks of a required shape by supplying ice-making water, from below, to multiple small ice compartments that are open downward, and a flow-down type automatic ice machine that causes ice-making water to flow down on the top surface of an inclined ice-making plate to produce a plate of ice on the ice-making plate.
For example, as shown in FIG. 11, there is an injection type automatic ice maker that is provided with what is called a closed-cell type ice-making mechanism 13. The closed-cell type ice-making mechanism 13 is equipped with an ice compartment 10, as an ice-making unit, in which a large number of small ice compartments 12 open downward are defined, and a tiltable water tray 40 that is located below the ice compartment 10 and is pivotally supported on a support shaft 42. An ice-making water tank 44 for storing ice-making water supplied from a water supply section 43 is integrally provided at the bottom of the water tray 40. An evaporator 48 which is led out from a refrigeration system 46 is disposed in a meandering fashion on the upper surface of the ice compartment 10 so that a refrigerant from the refrigeration system 46 is supplied in circulation to the evaporator 48 to cool the ice compartment 10 to below the freezing point. The refrigeration system 46 includes a compressor CM, a condenser CD and an expansion valve EV. The discharge side of the compressor CM and the suction side of the evaporator 48 are connected by a bypass pipe 50 at which a hot gas valve HV is provided.
At the time of the ice-making operation of the automatic ice maker, ice-making water is injected to the individual small ice compartments 12 from the water tray 40 having the small ice compartments 12 closed from below to form ice blocks in the small ice compartments 12 that is cooled forcibly. At the time of the deicing operation, the water tray 40 is tilted obliquely downward to open the small ice compartments 12, and the hot gas valve HV is opened to supply hot gas from the compressor CM to the evaporator 48 to melt the frozen connection between the ice blocks and the small ice compartments 12 and drop the ice blocks into an underlying ice storage room by their own weights.
FIG. 12 is an exploded perspective view of the ice compartment 10 disposed in the injection type automatic ice maker. The ice compartment 10 fundamentally includes a box-shaped outer frame 14 that is open downward, and a lattice-shaped partition member 30 that is disposed in the outer frame 14 and defines the plurality of small ice compartments 12. Further, a cooling pipe 48 as the evaporator is disposed in close contact on the upper surface of the outer frame 14 in a meandering fashion. The ice compartment 10 is made by assembling the components such as the outer frame 14 formed in a required shape, the partition member 30 and the cooling pipe 48. That is, the ice compartment 10 is assembled by setting the partition member 30, assembled with a plurality of metal plates in a lattice shape, inside the outer frame 14 formed in a box shape by bending a metal plate, and disposing the cooling pipe 48 which is an elongated hollow pipe bent in a meandering fashion on the upper surface of the outer frame 14. Then, the outer frame 14 and the partition member 30 are joined together by means of caulking, brazing or the like, and the outer frame 14 and the cooling pipe 48 are joined by brazing. In the case of the caulking, projections 31 are provided at an upper portion of the partition member 30, caulking holes 16a are formed in the upper surface of the outer frame, and the projections 31, which are inserted into the caulking holes 16a to project from the upper surface of the outer frame 14, are crushed with a hammer or the like. Each of the partition plates 30a, 30b, which constitute the partition member 30, may be provided with an engagement piece, and engagement grooves that engage with the respective engagement pieces may be provided in those positions of the outer frame 14 which correspond to the engagement pieces to position both members 14, 30.
A metal material like copper having good heat conductivity is used for a basis material 17 (see FIG. 2) of the components of the ice compartment 10 such as the outer frame 14, the partition member 30 and the cooling pipe 48 to ensure good heat exchange with the refrigerant that circulates the interior of the cooling pipe 48. Since the basis material 17 made of copper or the like, which is excellent in heat conductivity, is easily rusted, a molten tin plated coating 11 is generally formed on the surface of the ice compartment 10 as an antirust treatment, as shown in enlargement in FIG. 2. The molten tin plated coating 11 is formed on the surface of the ice compartment 10 by entirely immersing the whole ice compartment 10, assembled with the individual components 14, 30, 48, in a tin bath mainly containing melted tin. This plating treatment may be performed separately for the individual components 14, 30, 48, in which case the ice compartment 10 is assembled with the individual components 14, 30, 48 which have been plated with molten tin. The automatic ice maker including an ice compartment subjected to the aforementioned molten tin plated coating on the surface is disclosed, for example, in Patent Document 1.